1. Field of the Invention
The present invention relates to a communication system, a communication apparatus, and a packet length control method.
2. Description of the Related Art
When data is transmitted/received between a transmitter and a receiver, the data may not be transmitted/received correctly due to communication channel characteristics, communication path congestion, and the like. In such a case, the transmitter may repeatedly perform retransmission processing of the data until the data is correctly transmitted to the receiver. However, if the size of the data is large, it is often difficult to transmit the data correctly even though the retransmission processing is repeated many times. In such a case, the transmitter divides the large size data into small size data, and then transmits the data. The small size data is more likely to be transmitted correctly than the large size data. Therefore, by dividing the data into small data and transmitting the small data, the data can be transmitted correctly.
When transmitting a plurality of divided data, the transmitter generates a packet individually for each divided data. The transmitter performs modulation on each packet by using a predetermined modulation method, and transmits the packets to the receiver. As the predetermined modulation method, for example, a phase shift keying method, an amplitude modulation method, and the like are used. The receiver receives a modulated signal transmitted from the transmitter, demodulates the modulated signal by using a predetermined method (for example, refer to Japanese Patent Application Laid-Open No. 2008-294730), and extracts the divided data included in each packet. When having received all the divided data, the receiver combines the divided data to restore the original data. By using a method as described above, data can be transmitted from the transmitter to the receiver with a relatively high possibility even if the communication environment is bad or the like.